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Endocrinology (including Diabetes)/LADA Diabetes and Ironman triathlons


Hi Sheri,
I returned to doing triathlons early last year and shortly after was diagnosed with LADA diabetes.  Since then I have competed in several sprint and olympic distance triathlons, four half Ironman races, and one Ironman race. My BG levels are stable, last A1C 5.8, height 6'1, my weight is 182 and body fat is 6%.  I am taking Lantus at night, 11 - 12 units, no fast acting insulin unless I have a very high blood count before a meal. I measure blood sugar 3 -4 times per day.

My concern is that, although I am doing OK in races, I am falling fall short of what I raced in the past.  When I do an individual swim race, bike race, or run, I do very well.  But when I combine the three as part of a triathlon I just seem to run out of fuel too soon.   And it's not an issue of taking on nutrition.  I usually take a combination of liquid EFS and either Powerbar Gel or EFS gel.  I also take salt tablets for longer races.  For longer events I am also taking in about 300 calories per hour.  It almost feels as if the fuel I'm taking in is not abosrbed into the blood system, although I don't feel a need to pee or anything else.  Before a race my BG is usually up to maybe 220 after breakfast.  At the end of the race it is anywhere from 80 to 120 so I'm not getting any lows either.  

Last weekend I raced in IM Cozumel.  After 7 hours of swimming and biking I started the run.  Four weeks ago I ran 20 miles at an 8:28 pace and felt fine.  Last weekend I ran at a 9:30 pace for 6 miles and then leg cramps came on so bad in my hamstrings and quads I ended up walking most of the marathon.  My heart rate averaged only 115 for the second half of the marathon so clearly I could have gone a lot faster if my legs were OK.  

THis has happened in other races where my legs cramp so badly i have to slow down.  How can I find out what is wrong with my system?  When I've had electrolytes tested during routine blood tests, everything is fine and within range.  But I feel that during exercise I'm losing a lot of something (maybe magnessium) but I can't know unless my blood is tested during exercise?  Do you know of a place I can go to have these kind of tests done so
I can figure out the best way to continue participating in these races and be competitive.

Maybe it means taking insulin during races, which I'd rather not do but walking with cramps for a half marathon is even worse.  

I'm getting very frustrated to the point I'm thinking of just giving it up and going back to some other hobbies.  

THanks for any help,


  I feel your frustration, and I can sympathize.  Before you even mentioned it as I was reading through your concerns, magnesium came to mind.  I would suggest that you start taking a magnesium supplement and see if that helps.  I have heard of diabetic athletes (of all ages) having a problem similar to what you are experiencing.  I think the problem is not what you're taking in during a race, but rather your body's ability to fully recover and restore muscle glycogen levels during non-exercise times.  That may be limited by not having optimal blood glucose control at all times (such as by not taking insulin with meals).  Your A1C is in a prediabetic range, but it's not normal for highly-trained athletes.
  So, I would suggest that you try two things and see how it works for you.  First, get a slow-release magnesium supplement and start taking that daily.  Also, for a couple of days, check your blood glucose before, one and two hours after all your meals to see how it's doing.  If you're going above 140 mg/dl at any of those times, you may simply just not have enough insulin to restore glycogen at 100%.  That seems particularly evident to me at this point because of the fact that you don't have issues with shorter events.  Finally, if you have not read my book called Diabetic Athlete's Handbook (you can find out more about it on my web site at, you might want to do that just to get a better understanding of the physiology behind everything your body is going through during exercise.  Don't get a new hobby quite yet!  Sheri

Endocrinology (including Diabetes)

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Sheri Colberg, PhD


I am an exercise physiologist with a PhD who specializes in diabetes--as such I CANNOT answer general questions about other endocrine problems as I am neither an expert in all areas of endocrinology nor am I a medical doctor. My expertise lies in answering questions about diabetes (of any type) and physical activity, so please limit your questions to those areas. I can help you if you want to begin exercise or if you're already a diabetic athlete, and I am prepared to respond to questions about physical activity to which even your diabetologist may not know the answer. I can give suggestions about changes in your diabetic medications that differing types and intensities of exercise may necessitate, but I will have to refer you to your regular health care team to get final approval to make such changes. I can also answer questions about physical fitness, exercise metabolism, prediabetes reversal, and prevention of type 2 diabetes and diabetic complications.


I have both personal and professional experience in the areas of diabetes and exercise/physical activity. On a personal level, I have had type 1 diabetes since 1968, and I have been an avid exerciser since I was a child. Professionally, I have been conducting clinical studies on diabetes and exercise since 1992, largely with funding from the American Diabetes Association. I am also the author of 8 books related to diabetes, exercise, and more: The Diabetic Athlete (2001), Diabetes-Free Kids (2005), The 7 Step Diabetes Fitness Plan (2006), 50 Secrets of the Longest Living People with Diabetes (2007), The Science of Staying Young (2007), Matt Hoover's Guide to Life, Love, and Losing Weight (2008), Diabetic Athlete's Handbook (2009), and Diabetes? No Problema! (2009).

I am a Fellow of the American College of Sports Medicine, a professional member of the American Diabetes Association (and professional volunteer for the ADA), and a former member of the Board of Directors of the Diabetes Exercise & Sports Association.

I have published research and review articles in the following journals and magazines: Diabetes Care, Diabetes, Journal of Diabetes & Its Complications, Diabetes Self-Management, Medicine & Science in Sports & Exercise, Journal of Applied Physiology, The Physician and Sportsmedicine, Journal of Clinical Investigation, International Journal of Obesity, FASEB Journal, The Diabetes Educator, Journal of Physical Education, Recreation, and Dance, Clinical Exercise Physiology, Clinical Diabetes Reviews, Insulin, ACSM's Health & Fitness Journal, Biomechanics, On the Cutting Edge, Diabetes Technology & Therapeutics, Microvascular Research, Drug Benefit Trends, ACSM Certified News, Diabetes Health, SportEX Health, Diabetes Focus, Diabetes In Control, dLife-For Your Diabetes Life, Pediatrics for Parents, and My TCOYD (Taking Control of Your Diabetes) Newsletter. I have also been interviewed in myriad other magazines, such as Men's Health, Men's Fitness, Diabetes Forecast, Countdown Magazine, Joe Weider's Muscle & Fitness, Health, Tidewater Parent, Barron's News, Diabetes New Day, and Newsweek International.

I have an undergraduate degree (1985) from Stanford University, a Master's degree in exercise physiology (1987) from the University of California, Davis, and a Ph.D. (1992) from the University of California, Berkeley, in the same field. I also spent two years in an NIH-funded postdoctoral research position in endocrinology (studying obesity, diabetes, metabolism, and exercise) at the University of Pittsburgh School of Medicine (1993-1994).

Awards and Honors
Fellow, American College of Sports Medicine (FACSM) - 1996 Old Dominion University Darden College of Education Young Investigator Grant Award 2003 Honor Society of Phi Kappa Phi, Old Dominion University Chapter 2004-Present Great Women of the 21st Century by the American Biographical Institute 2005 Edition Old Dominion University Darden College of Education Largest Research Grant Award 2006 Old Dominion University Darden College of Education Publications Award (for greatest number) 2006 Saint Louis University, The Max K. Horwitt Memorial Lecture Distinguished Lectureship Award 2008 Old Dominion University Darden College of Education Publications Award 2009 Old Dominion University Darden College of Research Grants Award 2009

Past/Present Clients
I have consulted for numerous groups, including Can-Am Care, Numera|Social, California Commission on Peace Officer Standards and Training(about candidates with diabetes), Animas Corporation (an insulin pump company), Therasense, Inc. (makers of the Freestyle blood glucose meters), Council of Healthcare Advisors, and the City of Chesapeake (Virginia) Health Department.

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